'Walking Dead' Adds 'Wire' Vet to Play Pivotal Comic Character for Season 4

Larry Gilliard Jr. has booked the series regular role of Bob, a former Army medic who winds up becoming a key character for the Governor in the Robert Kirkman comics on which the series is based.

AMC's The Walking Dead is expanding its ranks.

Following the show's bloody fourth season that claimed the lives of multiple series regulars, The Wire's Larry Gilliard Jr. has been tapped to join the ranks of the zombie drama, The Hollywood Reporter has learned.

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Gilliard will play the series regular part of Bob Stookie, a former Army medic who is deeply haunted by his past -- both before and after the apocalypse. He's a loner though he maintains a charming yet self-deprecating and confident façade. In the Walking Dead comics, the Bob Stookey was a Woodbury resident (and alcoholic) responsible for saving the Governor's life after he was tortured by Michonne.

The 42-year-old actor's credits include HBO's The Wire, where he played D'Angelo Barksdale and co-starred alongside Walking Dead's Chad Coleman (Tyreese).

The casting comes just weeks after Walking Dead promoted Coleman, Sonequa Martin-Green (Sasha) and Emily Kinney (Beth) to series regulars and upped Melissa Ponzio (Karen) to recurring guest star for its fourth season. Coleman joined the series in November in a recurring role as fan favorite Tyreese, who first appeared in the seventh issue of Robert Kirkman's long-running Image comic. David Morrisseyis also slated to return as the show's central villain, The Governor, after what was initially perceived to be a one-season stint.

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During its record-breaking third season, Walking Dead lost a long roster of characters. In addition to Laurie Holden (Andrea) -- who had been with the series since its 2010 premiere -- Rick's wife Lori (Sarah Wayne Callies) shockingly was k!lled off in early in its third year along with regular T-Dog (IronE Singleton), among other recurring players including Daryl's (Norman Reedus) brother Merle (Michael Rooker).

Gilliard, whose credits also include The Machinist, Gangs of New York, Army Wives and Southland is repped by Innovative Artists and Thruline Entertainment. International Digital Times first reported Gilliard was in talks for the role.